/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package ai.platon.pulsar.crawl.signature;

import java.nio.ByteBuffer;
import java.util.Comparator;

public class SignatureComparator implements Comparator {

    public static int compare(byte[] data1, byte[] data2) {
        if (data1 == null && data2 == null)
            return 0;
        if (data1 == null)
            return -1;
        if (data2 == null)
            return 1;
        return _compare(data1, 0, data1.length, data2, 0, data2.length);
    }

    public static int compare(ByteBuffer buf1, ByteBuffer buf2) {
        if (buf1 == null && buf2 == null)
            return 0;
        if (buf1 == null)
            return -1;
        if (buf2 == null)
            return 1;
        return _compare(buf1.array(), buf1.arrayOffset() + buf1.position(),
                buf1.remaining(), buf2.array(), buf2.arrayOffset() + buf2.position(),
                buf2.remaining());
    }

    public static int _compare(Object o1, Object o2) {
        if (o1 == null && o2 == null)
            return 0;
        if (o1 == null)
            return -1;
        if (o2 == null)
            return 1;
        if (!(o1 instanceof byte[]))
            return -1;
        if (!(o2 instanceof byte[]))
            return 1;
        byte[] data1 = (byte[]) o1;
        byte[] data2 = (byte[]) o2;
        return _compare(data1, 0, data1.length, data2, 0, data2.length);
    }

    public static int _compare(byte[] data1, int s1, int l1, byte[] data2,
                               int s2, int l2) {
        if (l2 > l1)
            return -1;
        if (l2 < l1)
            return 1;
        int res = 0;
        for (int i = 0; i < l1; i++) {
            res = (data1[s1 + i] - data2[s2 + i]);
            if (res != 0)
                return res;
        }
        return 0;
    }

    public int compare(Object o1, Object o2) {
        return _compare(o1, o2);
    }
}
